Feeder monitor and feeder monitoring network

An animal feeder has a hopper for storing pieces of food. The bottom of the hopper has an opening accessible by an animal. The opening is smaller than a piece of food, but large enough for the animal to gnaw the food through the opening. The hopper has a surface adjacent the opening, to receive fallen gnawed food and hold the fallen gnawed food in a position accessible by the animal for eating. The hopper engages a mounting bracket. The bracket is directly attachable to the animal's cage. The bracket has a lip which partially covers the receiving surface of the hopper to physically limit the animal from leaning on the hopper and to prevent the hopper from tipping back so far that it falls off the conical mount. A conical bottom surface is attached to the hopper. The conical bottom surface seats on a conical mount. The conical mount transmits a downward force from the conical bottom surface to a sensor, but does not transmit an upward force or moment to the sensor. The average weight of the hopper and the variance or standard deviation of the sensor output signal are calculated by an embedded processor, based on the output of the sensor. The beginning and end of a feeding are determined based on the standard deviation. The amount of the food consumed by the animal during the feeding is calculated. Each feeder has a respective gate. The animal can access food when the gate is open, but not when the gate is closed. A plurality of actuators automatically open and close each gate in response to control signals. A plurality of animals, each in an individual cage with a separate hopper, are simultaneously monitored and data are periodically accessed by a host computer.